termcap.5

Unix操作系统minix 2.0源码

TERMCAP(5)                Minix Programmer's Manual                 TERMCAP(5)


     Row or column absolute cursor addressing can be given as single parameter
     capabilities  ch (horizontal position absolute) and cv (vertical position
     absolute).  Sometimes these  are  shorter  than  the  more  general  two-
     parameter  sequence (as with the Hewlett-Packard 2645) and can be used in
     preference to cm.  If there are parameterized local motions (e.g., move n
     positions  to  the right) these can be given as DO, LE, RI, and UP with a
     single parameter indicating  how  many  positions  to  move.   These  are
     primarily  useful if the terminal does not have cm, such as the Tektronix
     4025.

     Cursor Motions

     If the terminal has a fast way to home the cursor (to the very upper left
     corner of the screen), this can be given as ho.  Similarly, a fast way of
     getting to the lower left-hand corner  can  be  given  as  ll;  this  may
     involve  going  up  with  up from the home position, but a program should
     never do this itself (unless ll does), because it can make no  assumption
     about the effect of moving up from the home position.  Note that the home
     position is the same as cursor address (0,0): to the top left  corner  of
     the  screen,  not  of memory.  (Therefore, the "\EH" sequence on Hewlett-
     Packard terminals cannot be used for ho.)

     Area Clears

     If the terminal can clear from the current position to  the  end  of  the
     line, leaving the cursor where it is, this should be given as ce.  If the
     terminal can clear from the current position to the end of  the  display,
     this  should  be  given  as  cd.   cd must only be invoked from the first
     column of a line.  (Therefore, it can be simulated by a request to delete
     a large number of lines, if a true cd is not available.)

     Insert/Delete Line

     If the terminal can open a new blank line before the line containing  the
     cursor,  this  should  be given as al; this must be invoked only from the
     first position of a line.  The cursor must then appear at the left of the
     newly blank line.  If the terminal can delete the line that the cursor is
     on, this should be given as dl; this must only be  used  from  the  first
     position  on  the line to be deleted.  Versions of al and dl which take a
     single parameter and insert or delete that many lines can be given as  AL
     and  DL.   If  the  terminal  has  a  settable scrolling region (like the
     VT100), the command to set this can be described with the cs  capability,
     which  takes  two  parameters:  the top and bottom lines of the scrolling
     region.  The  cursor  position  is,  alas,  undefined  after  using  this
     command.  It is possible to get the effect of insert or delete line using
     this command -- the sc and rc (save and restore cursor) commands are also
     useful.   Inserting  lines at the top or bottom of the screen can also be
     done using sr or sf on many terminals without a true insert/delete  line,
     and is often faster even on terminals with those features.



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TERMCAP(5)                Minix Programmer's Manual                 TERMCAP(5)


     If the terminal has the ability to define a  window  as  part  of  memory
     which all commands affect, it should be given as the parameterized string
     wi.  The four parameters are the starting and ending lines in memory  and
     the starting and ending columns in memory, in that order.  (This terminfo
     capability is described  for  completeness.   It  is  unlikely  that  any
     termcap-using program will support it.)

     If the terminal can retain display memory above the screen, then  the  da
     capability should be given; if display memory can be retained below, then
     db should be given.  These indicate that deleting a line or scrolling may
     bring  non-blank  lines  up from below or that scrolling back with sr may
     bring down non-blank lines.

     Insert/Delete Character

     There are two basic  kinds  of  intelligent  terminals  with  respect  to
     insert/delete  character  that  can be described using termcap.  The most
     common insert/delete character operations affect only the  characters  on
     the  current  line  and shift characters off the end of the line rigidly.
     Other terminals, such as the Concept-100 and the Perkin Elmer Owl, make a
     distinction between typed and untyped blanks on the screen, shifting upon
     an insert or delete only to an untyped  blank  on  the  screen  which  is
     either  eliminated  or expanded to two untyped blanks.  You can determine
     the kind of terminal you have by clearing the  screen  then  typing  text
     separated  by  cursor  motions.   Type  "abc    def"  using  local cursor
     motions (not spaces) between the "abc" and the "def".  Then position  the
     cursor  before  the "abc" and put the terminal in insert mode.  If typing
     characters causes the rest of the line to shift rigidly and characters to
     fall  off the end, then your terminal does not distinguish between blanks
     and untyped positions.  If the "abc" shifts over to the "def" which  then
     move together around the end of the current line and onto the next as you
     insert, then you have the second type of terminal  and  should  give  the
     capability  in,  which  stands  for  "insert  null".  While these are two
     logically separate attributes (one line vs. multi-line insert  mode,  and
     special  treatment  of  untyped  spaces), we have seen no terminals whose
     insert mode cannot be described with the single attribute.

     Termcap can  describe  both  terminals  that  have  an  insert  mode  and
     terminals  that  send  a  simple sequence to open a blank position on the
     current line.  Give as im the sequence to get into insert mode.  Give  as
     ei  the  sequence to leave insert mode.  Now give as ic any sequence that
     needs to be sent  just  before  each  character  to  be  inserted.   Most
     terminals  with a true insert mode will not give ic; terminals that use a
     sequence to open a  screen  position  should  give  it  here.   (If  your
     terminal  has both, insert mode is usually preferable to ic.  Do not give
     both  unless  the  terminal  actually  requires  both  to  be   used   in
     combination.)  If post-insert padding is needed, give this as a number of
     milliseconds in ip (a string option).  Any other sequence that  may  need
     to be sent after insertion of a single character can also be given in ip.
     If your terminal needs to be placed into an `insert  mode'  and  needs  a


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TERMCAP(5)                Minix Programmer's Manual                 TERMCAP(5)


     special code preceding each inserted character, then both  im/ei  and  ic
     can  be  given,  and  both  will  be  used.   The IC capability, with one
     parameter n, will repeat the effects of ic n times.

     It is occasionally necessary to move  around  while  in  insert  mode  to
     delete  characters  on  the  same line (e.g., if there is a tab after the
     insertion position).  If your terminal  allows  motion  while  in  insert
     mode,  you can give the capability mi to speed up inserting in this case.
     Omitting mi will affect only speed.  Some terminals (notably Datamedia's)
     must not have mi because of the way their insert mode works.

     Finally, you can specify dc to delete a single  character,  DC  with  one
     parameter  n  to delete n characters, and delete mode by giving dm and ed
     to enter and exit delete mode (which is any mode the terminal needs to be
     placed in for dc to work).

     Highlighting, Underlining, and Visible Bells

     If your terminal has one or more kinds of display attributes,  these  can
     be  represented  in  a  number  of different ways.  You should choose one
     display form as standout mode, representing a good  high-contrast,  easy-
     on-the-eyes  format  for  highlighting error messages and other attention
     getters.  (If you have a choice, reverse video plus half-bright is  good,
     or  reverse  video alone.)  The sequences to enter and exit standout mode
     are given as so and se, respectively.  If the code to change into or  out
     of  standout  mode  leaves  one  or  even  two  blank  spaces  or garbage
     characters on the screen, as the TVI 912 and Teleray  1061  do,  then  sg
     should be given to tell how many characters are left.

     Codes to begin underlining and end underlining can be given as us and ue,
     respectively.   Underline mode change garbage is specified by ug, similar
     to sg.  If the terminal has a code to underline the current character and
     move  the  cursor  one position to the right, such as the Microterm Mime,
     this can be given as uc.

     Other  capabilities  to  enter  various  highlighting  modes  include  mb
     (blinking),  md  (bold  or  extra  bright),  mh  (dim or half-bright), mk
     (blanking or invisible text), mp  (protected),  mr  (reverse  video),  me
     (turn  off all attribute modes), as (enter alternate character set mode),
     and ae (exit alternate character set mode).   Turning  on  any  of  these
     modes singly may or may not turn off other modes.

     If there is a sequence to set arbitrary combinations of mode, this should
     be  given as sa (set attributes), taking 9 parameters.  Each parameter is
     either 0 or 1, as the corresponding attributes  is  on  or  off.   The  9
     parameters are, in order: standout, underline, reverse, blink, dim, bold,
     blank, protect, and alternate character  set.   Not  all  modes  need  be
     supported  by  sa,  only those for which corresponding attribute commands
     exist.  (It is unlikely that a termcap-using program  will  support  this
     capability, which is defined for compatibility with terminfo.)


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TERMCAP(5)                Minix Programmer's Manual                 TERMCAP(5)


     Terminals with the "magic cookie"  glitches  (sg  and  ug),  rather  than
     maintaining extra attribute bits for each character cell, instead deposit
     special "cookies", or  "garbage  characters",  when  they  receive  mode-
     setting sequences, which affect the display algorithm.

     Some terminals, such as the  Hewlett-Packard  2621,  automatically  leave
     standout  mode  when  they  move  to  a  new  line  or when the cursor is
     addressed.  Programs using standout mode should  exit  standout  mode  on
     such  terminals  before  moving  the  cursor  or  sending  a newline.  On
     terminals where this is not  a  problem,  the  ms  capability  should  be
     present to say that this overhead is unnecessary.

     If the terminal has a way of flashing the screen  to  indicate  an  error
     quietly  (a  bell replacement), this can be given as vb; it must not move
     the cursor.

     If the cursor needs to be made more visible than normal when it is not on
     the bottom line (to change, for example, a non-blinking underline into an
     easier-to-find block or blinking underline), give this  sequence  as  vs.
     If  there  is a way to make the cursor completely invisible, give that as
     vi.  The capability ve, which undoes the effects of both of these  modes,
     should also be given.

     If your  terminal  correctly  displays  underlined  characters  (with  no
     special codes needed) even though it does not overstrike, then you should
     give the capability ul.  If overstrikes are erasable with a  blank,  this
     should be indicated by giving eo.

     Keypad

     If the terminal has a keypad that  transmits  codes  when  the  keys  are
     pressed,  this information can be given.  Note that it is not possible to
     handle terminals where the keypad only works in local mode (this applies,
     for  example, to the unshifted Hewlett-Packard 2621 keys).  If the keypad
     can be set to transmit or not transmit, give these codes as  ks  and  ke.
     Otherwise  the  keypad  is assumed to always transmit.  The codes sent by
     the left-arrow, right-arrow, up-arrow, down-arrow, and home keys  can  be
     given  as  kl,  kr,  ku, kd, and kh, respectively.  If there are function
     keys such as f0, f1, ..., f9, the codes they send can  be  given  as  k0,
     k1,...,  k9.  If these keys have labels other than the default f0 through
     f9, the labels can be given as l0, l1,..., l9.  The codes transmitted  by
     certain other special keys can be given:  kH (home down), kb (backspace),
     ka (clear all tabs), kt (clear the tab stop in this  column),  kC  (clear
     screen  or  erase),  kD  (delete  character),  kL (delete line), kM (exit
     insert mode), kE (clear to end of line), kS (clear to end of screen),  kI
     (insert  character  or  enter  insert  mode),  kA (insert line), kN (next
     page),  kP  (previous  page),  kF  (scroll  forward/down),   kR   (scroll
     backward/up),  and  kT  (set a tab stop in this column).  In addition, if
     the keypad has a 3 by 3 array of keys including the four arrow keys, then
     the  other  five keys can be given as K1, K2, K3, K4, and K5.  These keys


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TERMCAP(5)                Minix Programmer's Manual                 TERMCAP(5)


     are useful when the effects of a 3 by 3 directional pad are needed.   The
     obsolete  ko  capability  formerly used to describe "other" function keys
     has been completely supplanted by the above capabilities.

     The ma entry is also used to indicate arrow keys on terminals  that  have
     single-character  arrow keys.  It is obsolete but still in use in version
     2  of  vi  which  must  be  run  on  some  minicomputers  due  to  memory
     limitations.   This  field  is redundant with kl, kr, ku, kd, and kh.  It
     consists of groups of two characters.  In each group, the first character
     is what an arrow key sends, and the second character is the corresponding
     vi command.  These commands are h for kl, j for kd, k for ku, l  for  kr,
     and  H  for  kh.   For  example,  the  Mime  would have "ma=^Hh^Kj^Zk^Xl"
     indicating arrow keys left (^H), down (^K),  up  (^Z),  and  right  (^X).
     (There is no home key on the Mime.)

     Tabs and Initialization

     If the terminal needs to be in a special mode when running a program that
     uses  these  capabilities,  the  codes to enter and exit this mode can be
     given as ti and te.  This arises, for example, from  terminals  like  the
     Concept  with  more  than  one  page of memory.  If the terminal has only
     memory-relative  cursor  addressing  and   not   screen-relative   cursor
     addressing,  a  screen-sized  window  must  be fixed into the display for
     cursor addressing to work properly.  This is also used for the  Tektronix
     4025, where ti sets the command character to be the one used by termcap.